Arable News

Written by: Farmers Guide

Posted: July 30, 2015

Making more money out of rape

Yield-protecting traits in leading oilseed rape varieties show that modern genetics can add 25/t to the bottom line

Financial valuations of key output-enhancing and yield-protecting traits in leading oilseed rape varieties show that modern genetics can add 25/t to the bottom line of the UK crop growing in the current season – and that’s before accounting for any gross output advantage.This was the message from Dekalb’s NW Europe seed and traits marketing head Deryn Gilbey (left) at a recent industry briefing.He says: “There’s no getting away from the fact that the crop has become increasingly expensive to grow for many, while remaining more variable in its delivery than other combinable cereal breaks.“Our key challenge as an industry has to be to make the crop more economically and environmentally resilient.”With the high-oleic, low-linolenic variety V316OL at the very top of this year’s East and West Recommended List on gross output alone, the opportunity to increase earnings by about 10 per cent without any risk by growing it or one of its high-output HOLL stable-mates on contract for premium food oil markets is clear.Dekalb’s oilseed rape project lead Kuldip Mudhar (left) says: “The opportunities for pod-shatter resistance, first-class disease resistance, vigorous establishment and fast leaf development in our mainstream double-low varieties offer production cost savings that are at least as significant.“Trials undertaken by NIAB TAG at two sites with eight of today’s top hybrid varieties under notably low shatter conditions last season really underline the value of pod-shatter resistance.“Our four pod-shatter resistant hybrids yielded almost identically to the non-resistant controls when harvested on 23-24 July.“When harvesting was delayed for six to seven days, however, the non-resistant varieties yielded six per cent less than the resistant ones. That gap widened to nine per cent after a further five- to seven-day harvest delay.“Even assuming a very conservative 4t/ha (1.6t/acre) initial yield, that represents a yield saving of just under 0.25t/ha (0.1t/acre). Which is almost 16/t at a rapeseed value of 265/t.“It goes to show how valuable pod-shatter resistance can be in allowing harvesting to be delayed without risk, to take full advantage of the longest-possible pod-fill.“We know that many growers desiccate a good week too early in the interests of security, and every day of pod-filling lost reduces yields by one to two per cent. We also know that seeds accumulate most of their oil in the second half of seed filling.”Kuldip says extra potential savings of more than 11/t from the best modern genetics through economies in fungicide spraying and nitrogen bills.In normal practice he finds phoma and light leaf spot resistance of the highest order in varieties such as DK Extrovert and DK Exalte allow flexibility and a tailored approach in their fungicide regimes, so that only two rather than three foliar sprays are needed in a moderate disease season.And, where higher disease pressures require a three-spray programme, their superior resistance allows a less expensive fungicide mix to be used.On average at current fungicide prices and spraying costs Kuldip calculates savings of about 6/t at 4t/ha (1.6t/acre).Likewise he typically sees vigorous growth and fast leaf development translate into a Green Area Index (GAI) advantage of 0.5t units, meaning about 25kg/ha (10kg/acre) less spring nitrogen is needed to achieve the optimum 3.5 GAI canopy at flowering.